Rotary fan



Nov. 6, 1951 7 R. G. RIDDIFORD 2,573,875

ROTARY FAN Filed Dec. 28, 1945 3 Sheets-Sheet 1 ,0 Has;

P HUD/F04 0 Nov. 6, 1951 R. cs. RIDDIFORD 2,573,875

v ROTARY FAN Filed Dec. 28, 1945 s Sheets-Sheet 2 Nov. 6, 1951 R. G.RIDDIFIORD 2,573,875

ROTARY FAN Filed Dec. 28, 1945 3 Sheets-Sheet 3 Patented Nov. 6, 1951ROTARY FAN Richard George Riddiford, Weybridge, England, assignor to TheAirscrew' Company Limited,

Weybridge, England Application December 28, 1945, Serial No. 637,570 InGreat Britain February 14, 1945 2 Claims. (01. 230-134) This inventionrelates to rotary fans and has for its object to provide an improvedconstruction of fan including an improved method of mounting the rotorblades or the blades of stationary guide vanes.

According to the present invention the mounting ring for the rotorblades or stationary guide blades comprises a series of detachablymounted segments. All, or only selected numbers of these segments areprovided with recesses to receive the roots of the blades or vanes. Eachrecessed segment may be in two parts, each having an open recess, thetwo parts being clamped, as by bolts, around the blade or vane rootsandto spaced side plates. By providing a series of interchangeable recessedand unrecessed segments it is possible for a range of fans having adifferent number of impeller blades or stationary vanes to be readilyassembled. Accordingly, the necessity of providing a separate rim foreach fan in the range is obviated and the cost of production reduced.

To enable the invention to be fully understood it will now be describedwith reference to the accompanying drawings, in which:

Fig. 1 is a front elevation of part of a fan rotor with the cover plateand one half of the two-part segments removed,

Fig. 2 is a section on the line 2-2 of Fig. 1,

Fig. 3 is a plan of one of the segment halves,

Fig. 4 is a view similar to Fig. 1 but shewing a different arrangementof the fan blades,

Fig. 5 is a front elevation of a hub plate shewing balancing means,

Fig. 6 is an elevation of part of a mounting ring for stationary guidevanes, and

Fig. '7 is a part sectional elevation of a fan unit.

As shewn in the accompanying drawings a fan rotor comprises a plate Ihaving a hub 2 which is keyed to a shaft 3, and a cover plate 4 which issecured to the shaft by a screw 5.

The plates 1 and 4 are spaced apart and provided with annular recesses6, 1 adjacent to the outer edges. A series of pairs of co-operatingsegments are assembled between the plates to form a blade mounting ring-As shewn, particularly in Fig. 3, each co-operating segment comprises ablock 8 having a concave recess 9 on its inner face and a projection II!on its outer face.

The pairs of segments are assembled round the cylindrical roots H of theblades [2 with the recesses encircling the roots. The projections I0 areentered into the respective recesses 5, l andsecured by bolts l3extending through the segments and plates I, 4. The bolts are finallytightened to clamp the blades, after the blade has been set to thedesired angle.

In Fig. 1 the fan rotor has 16 blades. If, however, a fan with 8, 4 or 2blades is required, it is merely necessary to replace the requisitenumber of blade-carrying segments by unrecessed spacer segments ofsimilar size. In Fig. 4 an arrangement of 12-b1aded fan is provided bythe use of short spacer segments l4 but it will be readily understoodthat by the use of spacer segments of different sizes it is possible tobuild up a fan having any desired number of blades.

An'important advantage of the present invention is that a wide range offans can be readily assembled, or existing fans altered to vary thenumber of blades, from a minimum number of parts, and without thenecessity of providing a complete one-piece blade mounting ring for eachtype of fan.

The spacer segments are preferably in one piece, as distinguished fromthe pairs of cooperating half blocks of the blade mounting segments. Theouter face of the spacer segments is preferably plane and unrecessed toavoid setting up undesirable eddy currents.

To enable the rotors to be balanced for each difierent arrangement ofblades, alternate webs l5 of the plate I are formed with radial slots ISin which weights I! are slidably mounted and clamped in adjustedposition as by bolts.

A modified form of balancing means is shewnin Fig. 5 whereincircumferential slots I8 are formed in the plate I in which weights l9are slidably mounted and locked as by bolts in adjusted position.

The outer edges of the spaced plates may be radiused in such a mannerthat the clearance between the edges and the blade is constantirrespective of the angular setting of the blade.

The application of the invention to stationary guide vanes is shewn inFig. 6 wherein the stationary vanes 20 are each mounted between halfblocks- 2! which are substantially similar to the half blocks 8. Thepairs of blocks are assembled round the roots 22 of the vanes 20 and theannular series of pairs of blocks are clamped between spaced plates 23,one only of which is shewn in Fig. 6. The mounting of the stationaryguide vanes will be substantially the same as that described above inconnection with the mounting of rotor blades.

A complete fan unit is shewn in Fig. 7 mounted in a casing 24 andcomprises a series of impeller blades 25 mounted in segments 26 whichare clamped between plates 21, 28 the plate 28 being keyed to the shaftof the electric motor 29. A series of stationary guide vanes 30 aremounted 'in front of the rotor blades and secured by bolts to the wallof the casing 24. The vanes 3|] are mounted in segments 31 which areclamped between spaced plates 32, 33 and a curved cover plate 34 issecured to the plate 32. If desired, the stationary guide vane unit maybe arranged behind instead of in front of the rotor blades.

I claim:

1. A mounting ring for the detachable reception of blades to functioneither as the rotor blades of a rotary fan or as stationary guide vanesin a fan unit, said mounting ring being in the form of a wheel-likestructure and comprising a series of blocks adapted on assembly to abutone against the other and form a continuous ring constituting the rim ofthe wheel-like structure and. also to provide a series of clamps forreleasably holding by their roots a predetermined number of blades sothat each blade is separately detachable and angularly adjustable by aturning movement about its axis, spaced side plates on opposite sides ofthe continuous ring of blocks. and of substantially the same diameter assaid ring and means for pulling said side plates together so as tovclamp tightly betweenthem the said blocks, the arrangement being such asto permit the number of blades to be varied and the continuity of thering'of blocks maintained.

2. A mounting ring for the detachable reception of blades to functioneither as the rotor blades of a rotary fan or as stationary guide vanes4 in a fan unit, said mounting ring being in the form of a wheel-likestructure and comprising a series of blocks adapted on assembly to abutone against the other and form a continuous ring constituting the rim ofthe Wheel-like structure some of said blocks comprising two co-operatingparts each providing half of a central cylindrical opening for receivingthe root of a blade to provide a series of clamps for releasably holdingby their roots a predetermined number of blades so that each blade isseparately detachable and angularly adjustable by a turning movementabout its axis, spaced side plates on opposite sides of the continuousring of blocks and of substantially the same diameter as said ring andmeans for pulling said side plates together so as to clamp tightlybetween them'the said blocks, the arrangement being such as to permitthe number of blades to be varied and the continuity of the ring ofblocks maintained by substituting a solid block for the blade engagingblocks from which a blade has been removed.

RICHARD GEORGE RIDDIFORD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,191,341 Curley Feb. 20, 19402,232,670 Barrett Feb. 18, 1941 2,298,576 McElroy et al Oct. 13, 19422,307,490 Curley Jan. 5, 1943 2,382,535 Bauer Aug. 14, 1945

